what is resonant tunneling diode | application of resonant tunneling diode

 

Introduction

Just as electronic devices are becoming smaller and faster, traditional semiconductor devices are also reaching their limits. We are facing this problem, and the solution to this problem is a quantum device, and among them, the most prominent is the RTD.

The RTD utilizes the principle of quantum tunneling and provides low power consumption at ultra-high speeds. Because of this, the RTD is considered an important part of nanoelectronics and future technology.

 

Description of a Resonant Tunneling Diode

A Resonant Tunneling Diode (RTD) is not just a quantum device but also a semiconductor device in which electrons tunnel only at specific energy levels.

As compared to a normal diode, an RTD possesses a specific characteristic called negative differential conductivity.

Simple Definition

Resonant Tunneling Diode: A resonant tunneling diode is a diode that works on the principles of quantum tunneling and the resonance effect.

 

Resonant Tunneling Diode Structure

The structure of an RTD is very simple, but it exists at the nano level:

• Thin potential barriers
• A quantum well in between
• Highly doped emitter and collector

Common Materials

Materials

• Gallium Arsenide (GaAs)
• Aluminum Gallium Arsenide (AlGaAs)

The thickness of the barriers is only a few nanometers, which makes quantum tunneling possible.

Working Principle of RTD Step-by-Step

The working of an RTD is based on quantum resonance. 

1. When voltage is applied, electrons gain energy.

2. Specified voltage/electron energy is confined to quantum wells, creating discrete energy levels.

3. In this condition, resonant tunneling occurs, and the current increases rapidly.

4. As the voltage increases further, the resonance breaks down.

5. Now the current decreases—a negative differential resistance region is obtained.

I-V Characteristics of Resonant Tunneling Diode

The current-voltage graph of an RTD is very distinctive:

• Peak current – ​​Tunneling point
• Valley current – ​​After loss of resonance
• Negative differential resistance region
• This NDR region is excellent for high-frequency circuits

 

Main Characteristics of RTD

• Quantum mechanical device

• Negative differential device

• Extremely fast switching speed

• Low Power Consumption

• Nanoscale size

• Terahertz frequency operation

 

Applications of Resonant Tunneling Diode

1. High-Speed ​​Oscillators

RTDs are used in microwave and terahertz oscillators.

2. High-Frequency Amplifiers

RTDs are used in millimeter wave and sub-millimeter wave amplifiers.

3. Logic Circuits

Multi-valued logic circuits can be implemented with RTDs, which are faster than traditional logic.

4. Memory Devices

RTDs are used in high-speed memory and latch circuits.

5. Communication Systems

RTDs are used in wireless and optical communication systems.

6. Nanoelectronics & Quantum Research

RTDs are intensively used in quantum computing and nanotechnology research.

 

Advantages of RTD

• Rapid response time
• Extremely small device size
• Low operating voltage
• High-frequency capacity
• Suitable for future nano ICs

 

Shortcomings in Resonant Tunneling Diode

• The fabrication process is complicated
• Temperature sensitive
• Limited output power
• Limited commercial use currently

 

Normal Diode & Resonant Tunneling Diode

 

Feature

1. Normal diode

Working Principle: Classical;

NDR: Not present;

Speed: Medium;

Scale: Micro scale

2. RTD (Resonant Tunneling Diode)

Working principle: Quantum;

NDR: present;

Speed: Very fast;

Size: Nano-scale.

 

Future Scope of RTD

RTD will have a major role in the future:

• Terahertz
• Quantum devices 
• Ultra-fast  
• Nano-communication

 

Conclusion

The resonant tunneling diode is one such quantum device which violates most of the main classical electronics rules. Their high speed, low power consumption and nano-scale nature have made them a game changer for future electronics devices. As technology increases in the atomic scale dimension, in a parallel way, devices such as will form the basis for next-generation electronics.